Search: fix header UI + instant typeahead (5 highlighted matches) + ranking

- Header search restyled as one clean RTL pill (input + button flush).
- Google-style autocomplete: typing ≥2 chars fetches /search/suggest and
  shows up to 5 live matches (round-robin across shifts/jobs/applicants)
  with the query highlighted, plus a «همه نتایج» link. Debounced, closes on
  outside-click/Escape.
- Search results page now RANKS by relevance (term hits in role/title/
  facility/city/tags weighted ×3, description ×1) instead of date-only.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/JobsMedical.Web/Pages/Shared/_Layout.cshtml

@@ -226,6 +226,51 @@
         });
     </script>
 
+    @* Instant search suggestions (typeahead) for the header search box. *@
+    <script>
+    (function () {
+        var form = document.querySelector('.nav-search');
+        if (!form) return;
+        var input = form.querySelector('input');
+        var box = document.createElement('div');
+        box.className = 'nav-search-results';
+        box.style.display = 'none';
+        form.appendChild(box);
+        var timer;
+        function esc(s) { var d = document.createElement('div'); d.textContent = s == null ? '' : s; return d.innerHTML; }
+        function hi(text, q) {
+            var safe = esc(text);
+            var terms = q.split(/\s+/).filter(function (t) { return t.length >= 2; })
+                .map(function (t) { return t.replace(/[.*+?^${}()|[\]\\]/g, '\\$&'); });
+            if (!terms.length) return safe;
+            try { return safe.replace(new RegExp('(' + terms.join('|') + ')', 'gi'), '<mark>$1</mark>'); }
+            catch (e) { return safe; }
+        }
+        function hide() { box.style.display = 'none'; box.innerHTML = ''; }
+        input.addEventListener('input', function () {
+            var q = input.value.trim();
+            clearTimeout(timer);
+            if (q.length < 2) { hide(); return; }
+            timer = setTimeout(function () {
+                fetch('/search/suggest?q=' + encodeURIComponent(q))
+                    .then(function (r) { return r.json(); })
+                    .then(function (items) {
+                        if (!items || !items.length) { hide(); return; }
+                        var html = items.map(function (it) {
+                            return '<a href="' + it.url + '"><span class="ns-type">' + esc(it.type) +
+                                '</span><span class="ns-label">' + hi(it.label, q) + '</span></a>';
+                        }).join('');
+                        html += '<a class="ns-all" href="/Search?Q=' + encodeURIComponent(q) + '">همه نتایج برای «' + esc(q) + '» ←</a>';
+                        box.innerHTML = html;
+                        box.style.display = 'block';
+                    }).catch(function () { hide(); });
+            }, 200);
+        });
+        document.addEventListener('click', function (e) { if (!form.contains(e.target)) hide(); });
+        input.addEventListener('keydown', function (e) { if (e.key === 'Escape') hide(); });
+    })();
+    </script>
+
     @* Live in-app notifications over SSE (our own origin — works in Iran, no Google push).
        Updates the bell badge, shows a toast, and fires a local OS notification when allowed. *@
     @if (User.Identity?.IsAuthenticated == true)